Funding for this research was provided by:
Luebeck Medical School (E18-2011)
Received: 18 December 2018
Accepted: 8 July 2019
First Online: 15 July 2019
Ethics approval and consent to participate
: This study was being conducted in accordance with the guidelines provided by the Declaration of Helsinki. The study protocol was approved by the Ethical Committee of the University of Lübeck (file reference: 11–010).
: Not applicable.
: The authors declare that they have no competing interests.